Server-Side Programming with JavaScript

What You’ll Learn 📚

• Core concepts of server-side programming
• Key terminology and definitions
• How to set up a basic server using Node.js
• Progressively complex examples to solidify your understanding
• Common questions and troubleshooting tips

Introduction to Server-Side Programming

Server-side programming involves writing code that runs on a server, handling requests from clients (like web browsers) and sending back responses. It’s a crucial part of web development, allowing you to create dynamic, interactive websites. With JavaScript, thanks to Node.js, you can use the same language on both the client and server sides, making development more streamlined and efficient. 😊

Key Terminology

• Server: A computer or system that provides data to other computers. In web development, a server hosts websites and serves them to users.
• Node.js: A JavaScript runtime built on Chrome’s V8 JavaScript engine, allowing you to run JavaScript on the server side.
• Request: A message sent by a client to a server asking for some resource or service.
• Response: The data sent back from the server to the client after processing a request.

Getting Started: Your First Server

Let’s start with the simplest example of creating a server using Node.js. Don’t worry if this seems complex at first; we’ll walk through it step by step. 😊

// Import the HTTP module
const http = require('http');

// Create a server object
const server = http.createServer((req, res) => {
  // Set the response header
  res.writeHead(200, {'Content-Type': 'text/plain'});
  // Send 'Hello World' as the response
  res.end('Hello World');
});

// The server listens on port 3000
server.listen(3000, () => {
  console.log('Server running at http://localhost:3000/');
});

Progressively Complex Examples

Now that you’ve got a basic server running, let’s build on that foundation with more complex examples.

const http = require('http');

const server = http.createServer((req, res) => {
  res.writeHead(200, {'Content-Type': 'text/html'});
  res.end('
Welcome to My Server
This is a simple HTML page.
');
});

server.listen(3000, () => {
  console.log('Server running at http://localhost:3000/');
});

const http = require('http');

const server = http.createServer((req, res) => {
  if (req.url === '/') {
    res.writeHead(200, {'Content-Type': 'text/html'});
    res.end('
Home Page
');
  } else if (req.url === '/about') {
    res.writeHead(200, {'Content-Type': 'text/html'});
    res.end('
About Page
');
  } else {
    res.writeHead(404, {'Content-Type': 'text/html'});
    res.end('
404 Not Found
');
  }
});

server.listen(3000, () => {
  console.log('Server running at http://localhost:3000/');
});

Common Questions and Troubleshooting

1. Why isn’t my server running?

   Ensure Node.js is installed and you’re running the correct command: node filename.js.

2. Why do I get a ‘port in use’ error?

   Another application might be using the same port. Try changing the port number in server.listen().

3. How can I stop the server?

   Press Ctrl + C in the terminal where the server is running.

4. Why isn’t my browser displaying the expected output?

   Clear your browser’s cache or try a different browser to ensure you’re seeing the latest changes.

Troubleshooting Common Issues

If you encounter errors, carefully check your code for typos or missing characters. JavaScript is case-sensitive, so require and Require are different!

Lightbulb Moment: Think of the server as a restaurant. The client (you) makes a request (order), the server (kitchen) processes it, and sends back a response (your meal). 🍽️

Practice Exercises

• Create a server that serves JSON data.
• Modify the server to handle more routes, such as a contact page.
• Experiment with different response headers and content types.

For more information, check out the Node.js documentation.

Keep experimenting and have fun with your server-side programming journey! 🎉